Re: [HEADSUP] big polling changes

From: Chuck Swiger <cswiger_at_mac.com>
Date: Fri, 07 Oct 2005 11:16:46 -0400
Gleb Smirnoff wrote:
> On Fri, Oct 07, 2005 at 06:10:26PM +0400, Yuriy N. Shkandybin wrote:
> Y> polling + kern.polling.idle_poll=1
> Y> CPU states:  0.2% user,  0.0% nice, 59.3% system, 21.3% interrupt, 19.2% 
> Y> idle
> Y> but about +10 %  perfomance thoughput
> 
> This is normal and known for idle_poll.

Is this because polling now fires the device interrupt every so often even 
while idle?

If so, could this behavior obtain a threshold to limit the maximum number of 
interrupts being added when the device is idle?  I've been seeing interupt 
storms back in 5.4, especially when a USB controller and a NIC share an IRQ.

Another thing to consider might be to switch in and out of polling mode 
dynamicly, which would let you operate in interrupt-driven mode if the network 
is quiet or silent, but would go into polling mode once there is enough traffic 
to make doing so a benefit.  Once you go into polling mode, stay there until 
the network becomes silent again.

-- 
-Chuck
Received on Fri Oct 07 2005 - 13:16:50 UTC

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